that might be the case but i still dont want that feature.

 

I have the same problems and reading through 17 pages of you guys describing it I'm postive I have the same problem. Thing is I'm in TX and there is no cold weather. As long as I can be assured this will not hurt or damage the car I guess I can get used to it. Who cares if somebody thinks I cant drive because the car revs freely by itself.

 

This revving problem, quickly worn out the sincro of the gearbox.
In my Evo 7, I changed the injector,with Marelli IWF1 type, and the revving disappears, the revs between gears change now, are going quickly down, and is a pleasure again to ride.

 

Some photo of the parts that solved this problem completely.

 

Those injectors, are a lot faster than the STD or the Trust(denso) 700cc. that I was using, but they need hight fuel pressure to be used properly(at least 8 bar).

 

It's been a while since I have looked at this thread, but are you guys starting to think that it is "sticky" injectors that was / is causing this problem? I remember asking a while back how many people with the problem used fuel additives....and perhaps it doesn't have to do with that, even. Maybe it's just the detergents put in the gas in your area, or lack of detergents. Anyway, injector cycle could very well have something to do with this, even though I have never experienced it.

Good luck, guys.

 

See, this is where it gets strange, because I can reproduce the problem easily by altering the spring pressure or swapping between different BOV's.. In my case, the excess pressure that isn't venting is sneaking into the intake through the partially open throttle blades or idle bypass.. I can completely make the symptoms go away by swapping a 1G DSM valve onto the car which is always partially open at idle, and opens very easily under vacuum.. an HKS SSQV is a good example of a Blowoff valve that will immediately close up tight once enough of the pressure purges to allow it to stay closed again, and on the SSQV, I can periodically reproduce this under light loads and part throttle, where boost is built, but for one reason or another, isn't given the opportunity to completely bleed off the pressure.. So it goes somewhere, either through the compressor (Surge) or force through the idle bypass, or both.. but only a small amount of pressurized air is needed to upset things.. When I was running a stock MAF, I would see this as a slight lean condition, but now with a blowthrough maf, I don't see it as anything except a slight raise in engine speed between shifts...

I think the injectors are part of the equation, but the combination of the extra fuel from a sticky injector (or in my case, the fact that the MAF is aware of this extra air due to the blowthrough sensor), and the extra air from the induction system getting through the idle bypass is enough to cause the engine to free-rev slightly between shifts.

But thats just my theory.. It just seems to make the most sense.

On some of the stock vehicles, I'm suspecting that maybe the DV may actually be more of a contributor, in some cases DV's have been installed backwards from the factory.. that could definitely contribute to this.. Others may just have a spring or other action in the valve that is binding (it is plastic and can become distorted).. Aftermarket DV's are a unique situation because it becomes a compromise between the spring pressure and boost keeping the valve closed at high boost pressures, and the ease of opening at part throttle and very low loads.. The reason I originally chose the HKS SSQV is because it doesn't rely on any sort of assistance to stay closed, but it opens easily under a vacuum.. It does have its share of issues, but thats for another topic.

 

Am I totally out in the blue here if I say that this problem can not be only in the injectors but also must be in the fact that the engine needs air as well as fuel to rev? Even if you have sticky or slow injectors the fuel alone could not cause the engine to rev?

I’ve had this problem on my car since I installed my turbo kit along with injectors and all the other parts. I’ve tested to disconnect the idle stepping motor just to rule it out as I never really though it could provide enough air to rev the engine to 6k-7k and that made absolutely no difference what so ever.

Today I will try to temporary install a supplementary spring to make sure the throttle is properly shut. This is the most likely theory in my opinion, i.e. that the high boost level makes the stock spring to weak to shut the throttle fast enough. If this doesn’t help I really have no more feasible ideas on what could cause this to happen.

 

Additional spring to the butterfly will be helpful, in my opinion.I hope you can solve this booring revving.

 

Well, we tested the extra spring idea and it seam to have cured my problems 100% I’m not sure if all people reporting similar problems have the exact same problem. In my case at least, this seam to have to do with the stock spring not being powerful enough to close the throttle fast enough. I’m boosting around 26-27psi with my 3071 and that seam to be too much for the spring to handle. I’m not saying that this could fix the problem for anybody else but it sure fixed it for me. I took some pictures on my installation, I’m sure it’s possible to make a nicer and stealthier installation but this was thought of as a temporary test BTW, that “flying saucer” looking thing is the Motec ALS throttle kicker, it’s actually just a vacuum bell that kicks the throttle open at the flip of a switch to provide enough air to have an effective anti lag.

 

wait so are you gonna get a more "suited" spring... like one that is same as stock but stronger?

as for the flying saucer.. HEHE that's ONE way to get the air to the unspent fuel, popopopop

hey did your 3071 end up "surging like a pig"

 

If I could find one I definitely would, but I’ll stick with this for awhile now until I know for sure that it’s ok. But I don’t have any sign of that revving problem since yesterday so I feel pretty confident for now

I run a pretty mild ALS for now, it saves the turbo, but even so it’s far better to use a throttle kicker than fixed throttle opening since the car is much smoother on idle and not that much of a pain to run in slow traffic etc.

Yes, I have some surge between about 3,5k and 4,5k rpm in 3rd and up, above that it goes away and in lower gears it revs past that spot so fast that it’s not even noticeable. It’s not that bad but there are some things that could be done to make it better or even go away completely. I could probably just fine tune the boost curve in 3rd, 4th and 5th, or I could get a ported shroud which would move the surge limit further to the left on the compressor map.

For the moment I’m just happy that my car is running pretty good and the revving problem seam to be solved, at least in this case

 

Its certainly worth a try.. I think people may be interested in why its doing it, and not so much a ad-hoc solution, but since I have the same symptoms and are likely caused for a similar reason, I'm going to try it.

 

The spring idea worked for me. I have the following setup:

-dynoFlash
-greddy type-s BOV


Thanks EVOVII_SWE.

BTW i attatched the spring a little differently (i have pics if anyone wants to see)

 

So additonal tension on the throttle butterfly works? All the people complaining about it and only two people posted that they tried the spring. I noticed the Evo throttle pedal felt considerably lighter than my MY96 STi so it makes a bit of sense if that were the case.

It is still entirely possible that it is ECU data. When a reflash is done, the "tuners" just alter the tables that they understand and/or have access to. Stuff like this can be implemented as a series of checks and jumps in assembly code or it may be table referenced in a way end-users could see and adjust.

-Jon